The invention relates to a device for performing measurements and/or taking samples in molten metals with a sublance, which has a sublance body, on whose one end a lance holder is arranged for receiving an immersion probe.
Such devices are sufficiently well known to those skilled in the art. They are used for measurements or taking samples in molten metals. Such sampling is partially automated, wherein a sublance is dipped into a melt container, after which the immersion probe arranged on the sublance is discarded, because it is used up, and a new immersion probe is placed on the sublance. In order to automate this procedure, the sublance must be able to be positioned exactly over a probe storage container.
In practice, however, it has been shown that, due to the loads exerted on a sublance during use, these sublances become slightly deformed, so that the lance holder can no longer be placed exactly over an immersion probe and the probe cannot be received without problems. The immersion probes placed on the sublances do not have the same exact length. In particular, the contact part housed in the carrier tube cannot always be reached at the same depth by the counter contact in the sublance. As a result, splashes of the molten metal frequently settle onto parts of the sublance, which must remain free for forming the contact, so that trouble-free placement of the immersion probes is impossible. This can disrupt the entire steel making process.
Sublances are known, for example, from European published patent application EP 69 433 A1. Here, an attempt is made to counteract the deformation of the sublance during the operation by rotating the sublance. The arrangement and function of sublances is further described in German published patent application DE 43 06 332 A1. Here, the exchanging procedure of the sample probes is also disclosed. Another sublance is known from European Patent EP 143 498 B1. The sublance described here has a seal, for example a rubber ring, at connection points, which prevents liquid metal from being able to penetrate into the mechanism.
The invention is based on the problem of improving the known sublances and especially enhancing the fail-safe means in automatic operation.